In a large bowl, stir together flour and salt. Add 400g margarine, 4 beaten eggs, evaporated milk, yeast and 4 tablespoons sugar. Mix as much as you can in the bowl, then turn out onto a floured surface and knead until smooth, about 5 minutes. Place into an oiled bowl, cover and chill overnight.
To make the filling: Melt 115g margarine and stir in sugar. Mix in the cinnamon and walnuts; remove from heat and set aside to cool. When the nuts are cooled, stir in the egg and just enough of the milk to moisten the filling.
Preheat oven to 180 C / Gas 4. Grease baking trays. Roll out dough to 5mm thickness. Sprinkle some of the remaining sugar over the dough. Cut into small triangles about 7.5cm long and 5cm at the base. Put a teaspoon of filling at the base of the triangle and roll towards the point. Roll in sugar and place 5cm apart onto the prepared baking trays.
Bake for 10 to 15 minutes in the preheated oven. Remove from baking trays to cool on wire racks.